#include <REGX52.H>

void Delay(unsigned int time);

void main(){
	
	unsigned char LEDNum = 0;
	
	P2 = ~(0x01);
	
	while(1) {
		if (P3_1==0) {
			Delay(20);
			while(P3_1==0);
			Delay(20);
			
			LEDNum++;
			
			if (LEDNum>=8) {
				LEDNum = 0;
			}
			
			P2 = ~(0x01<<LEDNum);
			
		}
		if (P3_0==0) {
			Delay(20);
			while(P3_0==0);
			Delay(20);
			
			
			if (LEDNum==0) {
				LEDNum = 7;
			} else {
				LEDNum--;
			}
			
			P2 = ~(0x01<<LEDNum);
			
		}
	}
}

void Delay(unsigned int time)		//@12.000MHz
{
	unsigned char i, j;

	i = 2;
	j = 239;
	do
	{
		while (--j);
	} while (--i);
}
